Portable computers such as lap-top and notebook type computers are characterized by a system unit which contains the CPU, disk drives, memory and other hardware, and a display unit which is pivotally attached to the system unit. Necessarily, the display unit is also electrically interconnected with the system unit by means of a flexible cable, a slip ring arrangement, or a pivotable electrical connector. Flexible cables are well known for suffering fatigue in such environments resulting in broken conductors that render the equipment unreliable or inoperative. Slip ring systems, on the other hand, are reliable but expensive to manufacture and require a substantial amount of space to implement. A pivotal connector, on the other hand, does not have these shortcomings and, as will be explained below, can have certain advantages such as easy installation or replacement. A pivotal connector may be integrated into the hinge structure of the computer or it may be a separate connector attached to the computer so that its pivot is axially aligned with the hinge. An example of the interconnection being integrated into the hinge is disclosed in U.S. Pat. No. 5,237,488 which issued Aug. 17, 1993 to Moser et al. There, the hinge pin itself has conductive tracks in the form of slip rings on its outer surface while the system and display units have conductive wipers that are in contacting engagement with the slip rings so that, as the display unit is pivoted about the hinge pin, electrical interconnection through the slip rings is maintained. Since the electrical connector is an integral part of the computer, it is difficult to repair or replace. Separate pivotal connectors, on the other hand, overcome this problem, and additionally have the advantage of being less expensive to manufacture. Such a separate pivotal connector is disclosed in U.S. Pat. No. 4,865,553 which issued Sep. 12, 1989 to Tanigawa et al. The '553 patent shows a receptacle connector having a U-shaped contact and a mating plug connector having a contact with a cylindrical portion that engages the U-shaped contact, making electrical contact on opposite points on its outer cylindrical surface. Such a cylindrical shaped contact having two points of contact is quit reliable but relatively expensive to manufacture. Another example of a separate pivotal connector is disclosed in U.S. Pat. No. 4,975,062 which issued Dec. 4, 1990 to Evans et al. The '062 patent discloses a connector having identical mating connector halves, each having identical contacts. The connector housings have a complementary hinge pin and hole so that when mated, the pin of one housing pivotally engages the hole of the other housing. The contacts are stamped and formed, each having a flat contact surface supported in the center of a beam that deflects when the contact mates with its corresponding mating contact. All of the contact force is provided by the single deflecting beam. While such a contact structure is suitable for many electrical applications, with only one point of contact, its reliability may suffer when used in environmental conditions conducive to contamination.
What is needed is a pivotal electrical connector that utilizes two point contacts with relatively high reliability yet is inexpensive to manufacture and is easily installed and replaced in the field.